1. Considering the following code snippet, can someone tell me what is going on?

@path{@INC} = ();
# Then later in the find sub, we see:
$File::Find::prune = 1,
return if exists $path{$File::Find::dir} and $File::Find::dir ne $File+::Find::topdir;
# What is going in the above line? What is the purpose?